OpenCode AI tab: spawns new `opencode serve` instead of reusing existing server (port conflict)

[alexey-igrychev]

Description

When using the AI tab in the code review UI with the OpenCode provider, Plannotator spawns a new opencode serve process instead of connecting to the already running OpenCode server.

Steps to reproduce

1. Start OpenCode normally (it listens on port 4096)
2. Open Plannotator code review (plannotator review or /plannotator-review)
3. Select OpenCode as the AI provider in the AI tab
4. Send a message

Expected behavior

Plannotator should connect to the already running OpenCode server on port 4096 (or whatever port it's using).

Actual behavior

Plannotator spawns a new opencode serve --hostname=127.0.0.1 --port=4096, which crashes because the port is already in use:

Server exited with code 1 Server output: Warning: OPENCODE_SERVER_PASSWORD is not set; server is unsecured.
Error: Unexpected error, check log file at /Users/.../.local/share/opencode/log/2026-04-07T183619.log for more details
Failed to start server on port 4096

The log file contains only 3 lines — the process crashes during config loading before it can detect the port conflict gracefully.

If OpenCode is not running, Plannotator successfully spawns a new server, but this leads to issue #514.

Environment

• Plannotator: v0.17.1 (CLI), @plannotator/opencode@latest (plugin)
• OpenCode: v1.3.15
• OS: macOS (Apple Silicon)
• Bun: v1.3.11

[oorestisime]

+1 this. Its currently not very usable. I opened opencode and did /plannotator-review with a PR and i was expecitng to have the session communicate. instead its basically needing an extra opencode serve?

Almost feels like the plannotator-review command shouldn't happen from opencode but exist as a cli and it might need to start opencode serve itself.